Electric circuit controller



May 31, 1949. e. B. LUTZ ELECTRIC CIRCUIT CONTROLLER Filed April 12, 1947 INVENTOR. 650/265 .5. ZUTZ Patented May 31, 1949 UNITED STATES PATENT OFFICE ELECTRIC CIRCUIT CONTROLLER George B. Lutz, Lakewood, Ohio Application A ril 12, 1947, Serial No. 741,115

19 Claims; 1

This invention relates to an electric circuit controller and more particularly to a means for automatically opening and closing the circuit to an electric lamp or other appliance at periodic intervals.

It is a well-known fact that the presence of a light in a residence or place of business tends to discourage burglars. This is probably due to a number of factors but in the case of a store or other business place the primary deterring iniluence is the fact that the light renders unauthorized visitors visible to pass'ers by. In the case of a residence, however, the primary deterring factor is no doubt due to the belief that the light indicates that an occupant of the house may still be awake. Where, however, the same li ht is allowed to'burn all night a burglar readily discerns this fact and is emboldened to attempt entry. If, however, the lamp be periodically switched on and oil it is difiicult to tell if the occupants of the residence be awake or asleep and thisis especially true where-different lights are turned on and off at difierent intervals.

It is, therefore, an object of the invention to provide a new and improved circuit controller comprising a unitary structure adapted to be connected with a conventional household outlet and which includes means for automatically periodically interrupting the circuit to a lamp or other appliance attached thereto.

In addition to its utility as a means of discouraging burglars, a light which is-periodi'cally turned on and off may be advantageously employed for advertising purposes or other uses, and a mechanism for effecting the opening and closing of the electrical circuit for a light islikewise useful for operating various other electrical appliances for predetermined time intervals.

Therefore, another object of the invention is to provide a novel and improved electric circuit controlling apparatus adapted to be connect'e'd with a source of electrical power and having means for automatically periodically opening and closing an electrical circuit for a lamp'or other appliance, and also having a manually operated switch means to bypass the mechanism for pcriodically interrupting the circuit to the appliance and provide a continuous circuit for the appliance.

An additional object of the invention is to provide a novel and improved electrical circuit controller comprising a unitary'structure adapted to be'connected with an electrical outlet and having a rotatable cam means, driven'by a timing mechanism, for automatically periodically opening and closing a circuit from the outlet to an appliance connected with said unit.

A more specific object of the invention is to provide a novel and improved electrical circuit controller of the type described in theprece'eding object and in which'said" timing mechanism com prises a clockwork mechanism for rotating the cam means, and said unit further comprises- It is also ancbject of the invention-to provide an electric circuit controller of the type described in the preceding objects which is attractive-in appearance; simple in operation and economical to manufacture.

The invention further resides in certai'n novel features, details of construction and combination and arrangements of parts; andfurther ob-'- jects and advantages thereof will be apparent to those skilled-inthe-art to Whichit pertains from thefollowing description of the presentpreferred embodiment, and certain modifications thereof; described with reference to the accompanying drawing in which similar reference characters represent corresponding parts throughout-eer eral'views, and in which:

Fig; 1 is a front elevationalview or an electric circuit controller embodying the invention;

Fig. 2'is an end elevational view of the circuit controller illustrated in Fig. 1';

Fig. 3 15 a rear elevational view of the circuitcontroller illustrated in Figs 1 and 2';

Fig.4 is a rearelevationalview of the circuitcontroller' illustratedin Figs. 1, 2 an'd 3-with the back cover thereof removed;

Fig; 5 is a diagrammaticalview illustrating'the electrical circuit of the controller;

Fig. 6 is a-detached' elevationalview of an adjustablecammeansfor useinan electric circuit controller of the type illustrated in Figs. 1 to 5 to'v'ary the duration of the intervals of circuit opening and closing;

Fig. '7 is a sectional view through a modified form of electric circuit controller in whichdif ferent "meansare provided for varyingthe aura-- 3 tion of the intervals of circuit opening and closing; and

Fig. 8 is a fragmentary sectional view taken substantially on the section line 8-8 of Fig. '7.

The present preferred embodiment of the electrical circuit controller of this invention, illustrated in Figs. 1 to 5, comprises a unitary housing or case, generally designated I0, which may be formed of plastic, plywood or other suitable material. This housing or case comprises a front panel side panels or flanges l2 and I3, top panel or flange [4, bottom panel or flange l5, and a rear panel l6. Preferably, as illustrated in the drawings, the front panel II, the side panels l2 and I3, and the top and bottom panels l4 and I5, are formed as a single unitary member and the rear corners of this member are provided with integral portions or bosses Each of these bosses is provided with a threaded opening l8 for receiving a screw or other fastening means I9 for attaching the rear panel |6.

As shown in Fig. 4, the interior of the housing H) is provided with a timing mechanism 20, which may comprise either an electrical or mechanical clockwork mechanism, the former being preferred. This timing mechanism is mounted substantially centrally of the housing, being connected to the rear face of the front panel thereof by suitable means such as screws 2| and 22 which may either pass through the face of the housing, as shown, or be threaded into suitable bosses on the rear face of the panel II for cooperation with suitable lugs or projections upon the frame member 23 of the timing mechanism. At one side of the timing mechanism, and adjacent the top of the housing, there is mounted a conventional electrical outlet receptacle 2d, the openings of which are accessible through the front panel I of the housing. Adjacent the other side of the timing mechanism 20 is mounted a two-way switch 25 which may be of a conventional double pole, snap-acting toggle switch provided with a toggle actuator 26 which extends through a suitable opening in the face I of the housing. Also connected with the rear face of the front panel I l of the housing is a pair of terminal members 21 and 28 which are adapted to extend through suitable openings in the rear panel l6 of the housing and constitute a plug for insertion into a conventional electrical power outlet of the type normally employed in baseboards and the like.

The timing mechanism 20 is provided with an output shaft 29, which in the present instance comprises the shaft upon which the hands of the clockwork are normally mounted. The hands have, however, been removed and in their place there is attached a cam 30 which is connected for rotation by the mechanism which ordinarily moves the minute hand of the clockwork. Consequently, the cam 30 will make one complete revolution for each hour that the timing mechanism 20 is energized. As shown in Fig. 4, the cam 30 is provided with a substantially arcuate raised portion 3| extending substantially 180 degrees about its periphery, the remainder of the periphery of the cam comprising a curved portion 32, having progressively smaller radii each less than the radius of the portion 3|, this portion 32 terminating in a relatively abrupt shoulder 33.

Mounted upon the frame 23 of the timing mechanism 20, adjacent the cam 30, is an electrical switch 34 which has a pair of normally open contacts. This witch, which may be of the type known as a micro switch, is provided with a movable operating arm 35, the outer end of the arm carrying a roller 36 positioned to ride upon the periphery of the cam 30. The arm 35 is biased by means, not shown, to maintain the roller in contact with the cam and the construction is such that when the cam 30 is rotated, in the direction indicated by the arrow in Fig. 4, the roller 36 riding upon the cam moves the arm 35 to close the circuit through the switch when the roller has reached the raised portion 3| of the cam. The switch contacts are held in their closed position while the roller 36 rides upon the raised portion 3| of the cam, and are opened when the roller 36 drops down the shoulder 33 and rides upon the portion 32 of the cam.

The timing or clockwork mechanism 2% is provided with a setting means which is employed in the present apparatus for effecting adjustment of the angular position of the cam relative to the roller 36. As illustrated in Fig. 4, this setting means comprises a pinion 3'! attached to the shaft 29 and meshing with an idler 38 mounted upon the outer face of the frame 23 of the clockwork mechanism. The idler 38 is adapter to be engaged by a pinion 39 which is connected with a shaft MB, and the latter is rotatably supported by a substantially U-shaped bracket 4| attached to the frame 23. The shaft 40 extends through an opening in the bottom l5 of the housing and is provided on its outer end with a knurled knob 42. Disposed between a shoulder or collar upon the shaft 40 and the lower leg of the bracket 4| is a coil spring i3 normally tending to disengage the pinion 39 from the idler 38. However, when the knob 32 is pushed inwardly against the force of the spring 43, the pinion 39 will mesh with the idler so that rotation of the knob 42 will enable the cam 3|] to be angularly adjusted to a desired position.

The several elements of the circuit controller are electrically interconnected in the manner illustrated in Figs. 4 and 5. That is, the terminal or plug member 27 is connected by a wire M with one terminal $5 of the outlet receptacle 2% to which the lamp or other appliance is to be connected. The other terminal 46 of the receptacle 24 is connected by a wire l! with one terminal 28 of the two-way switch 25. This terminal 48 is adapted to be connected with a terminal is of the switch by the movable switch blade 59 and the terminal is is connected by a wire 5| with the other terminal or plug member 28. Also connected with the terminal is one end of a wire 52, the other end of which is connected with one end of the coil 53 of the timing or clockwork mechanism 20. The other end of the coil 53 is connected by a wire 54 with the terminal 55 of the switch 25, the terminal 55 being adapted to be connected with the terminal 56 of the switch by the second movable blade 57 thereof. The terminal 56 of the switch 25 is connected by a wire 58 to the terminal or plug member 28.

Connected with the terminal 46 of the outlet 24 is one end of a wire 59, the other end of which is connected to one end of a switch blade 60 in the switch 34. This switch blade fill is operated by the previously mentioned arm 35 to and from engagement with a stationary contact 6 i. The contact SI of the switch 341' is connected by wire Bil to the terminal 55 of the switch 25.

In operation of the circuit controller, the terminal or plug members 2! and 28 are inserted in a conventional electrical power outlet and the lamp or other appliance which is to be controlled is connected with the outlet receptacle 24 provided in the housing iii. With the two-way switch *positioned as. shown, that is with the switch actuator 26 at the off position, the blade 59 of the switch is contact with the terminals and as. Ther fore a continuous circuit is provided from plug member 2? through wire terminal the lamp or other appliance connected to the terminals and it, the wire-5's, terminal switch blade terminal "39 and wire 5i to the other plug member 28. position of the switch 25, the or other anpliance is continuously energi ed in the same manner as though it were directly connected with the conventional outlet.

When the actuator 23 of the switch 25 is now moved to its on" position, the switch blade is moved from engagement with the ter inals and 4'9 and the switch blade 52 now engages the terminals 55 and 56. A circuit is therefore completed from the plug member 2? through the wires 44, 52, the coil 53 of the timing device iii, wire 5%, terminal 55, switch blade 5'5, terminal 56, and wire 58 to the other plug member 23. Hence, the timing device 28 is energized causing rotation of the shaft 29 and the cam 36 carried thereby. In the position of the cam and the switch 3 illustrated in Figs. 4 and 5, the circuit to the lamp or other appliance connected to the outlet 2 54 is now open so that the lamp or other appliance is not energized. As the cam Bil rotates, however, the roller 38 will eventually right upon the portion of the cam thus actuating the switch blade 59 into engagement with the contact bi so that a circuit is completed through the appliance con" nected to the outlet 2 blade iii; and contact iii of the switch 3 3, wire E52, terminal 55, switch blade 5?, terminal 56 and wires to the plug member 28. The lamp or other appliance will, therefore, remain energized until the cam has rotated sufficiently to allow the roller to drop down the shoulder portion 33 of the cam opening the circuit by moving the blade from engagement with the contact El.

So long as the switch 25 is left in its on po tion, the lamp or other appliance will be periodically energized and tie-energized by the operation of the cam 3b in movin the switch blade (56 as just described. Consequently, if a light be connected with a circuit controller, it will be illuminated for a predetermined period of time and then extinguished. By employing several such controllers for lights in diiierent parts of the house and originally adjusting each controller, by means of the knobs so that the several lights are energized at difierent the appearance is that of a person periodically moving about from room to room and turnin the lights on and The cam may have any d Fred shape to provide intervals of circuit 0103-19" and opening of desired duration. Thus, a single cam may be employed to open and close a circuit several t e during a single revolution, the durations of th opened and closed conditions of the circuit bein' either equal or unequal in length, in accordance with the shape of the cam. Moreover, w la the cam has been shown as attached for rota-no by the mechanism which normally the hand of the clockwork Ell so that the rotates once during each hour, it will be parent that the cam could also be positioned upon o mesh, which normally moves the hour hano of the ole work so that a complete revolution of car-hi requires 12 hours.

In place of providing a single cam of fixed configuration in a circuit controller constructed and 235.

sub tantially degrees of the cam, the remaining 2T0 degrees of each cam being formed by arcuate portion I 32, i32a, respectively, of er radius. Each of the cams is also provided with arcuate slots 233, i3 5 and lfia, 535a, respectively, disposed in the quadrants adjacent to that in which the raised portions liil, lisla are provided. The construction is such that the two c ms may be superimposed and connected toether by suitable means such as bolts i565 and 2 extending through the slots E33, 833a and a. Hence, the raised portions l3l, l3la f the cams be adjusted relative to each ther to provide different intervals of opening and closing of the circuit when this adjustable cam means is employed in place of the cam 36 in the cir uit controller illustrated in Figs. 1 to 5, i operation being otherwise the same as previously described.

Figs. 7 and 8 illustrate a modified fOl'll'i of circuit controller which is substantially the same t. disclosed in Figs. 1 to 5 except that the clockwori: shaft 29 is here provided with two rate cams 238 and 523i. In addition, the sv tch (it is no longer fastened to the framework of the timing or clockwork mechanism 28 but is supported by a rod 232 which has a polygonal cross section and is slidably received in a correspondingly shaped opening of a bracket or boss 233 attached to, or integral with, the rear cover or panel is of the housing Iii. The switch is therefore supported for cooperation with either of the cams 2-38) or 23!, the switch being 'etained from rotation by the polygonally shaped rod 2322. Alternatively, the switch may be supported by a pair of spaced rods slidably received within openings in suitable brackets or bosses. If more than one sup-porting rod be employed the and openings may be cylindrical.

The forward face of the switch is provided with a rod 23% which ext-ends through the front face ll of the housing, the outer end of the rod being provided with a knob 235. The rod 2% is provided, intermediate its ends, with a pair of spaced grooves 235 and 23'! which are spaced a distance equal to the spacing of the cams 238 Attached to the rear face of the front oel ll of the housing is a slidable latch or oetent member which is here illustrated as having a thickness substantially equal to the thickness of the grooves 236 and 23's, the upper end of the'detcnt having a substantially semicircular opening adapted to surround the reduced portion of shaft 234 formed by the grooves 23's. The lower portion of the latch or detent has a forwardly extending flange or projection i239 extending through an opening E la n the "out of the housing and the vertical por- "1 of the detent 238 has an elongated slot Mi -rough which passes a fastening means 262 by the detent is connected with the rear, face of the front panel l i. This fastening means may incv e a spring washer or the like, if desired, to .crcse the friction between the detent 238 and the surface of the housing.

The construction of this form of the controller is such that, with the parts in the positions illustrated in Fig. 7, the roller 36 of the switch 34 is positioned to ride upon the surface of the cam 23L the switch being held in this position by the engagement of the detent 238 with the groove 2% of the shaft 23%. When it is desired to have the switch 3d operated by the cam 230, the projection 239 of the latch 23% is moved downwardly within the opening B l-ii thus disengaging the latch from the groove 23$. The knob 235 is then grasped and pulled forwardly with respect to the housing Hi until the groove 23? aligns with the latch E38 and the latter is then raised into engagement with the groove 23'! by manipulation of the projection 239. The operation of this form of the controller is otherwise the same as that described for the embodiment illustrated in Figs. 1 to 5 and hence need not be repeated. In place of the slidable detent or latch 238 it will be apparent that a flexible spring detent or latch may be employed, the movement of the rod 234 then being effected by simply grasping the knob 235 and moving the rod 23 longitudinally, the detent flexing sufficiently to disengage it from one groove and to automatically re-enter the other groove when properly positioned as will be readily understood. Also, while two cams of fixed configuration have been disclosed in this embodiment, it will be apparent a greater number may be employed and/or the cams may be adjustable in the manner disclosed in Fig. 6.

While the invention has been described primarily with reference to its use in controlling the circuit for a light it will be readily apparent that it can be employed for controlling the circuit to other devices such as irons, heaters, and the like. I-i'ence, the term appliance is used in the subjoined claims in a generic sense to include both lamps and other electrical devices.

Although a preferred'embodiment and certain modifications of the invention have been described in considerable detail, it will be apparent that various other modifications, adaptations and utilizations of the device may be efiected by those skilled in the art to which the invention pertains. Therefore the invention is not to be considered as limited to the specific details of construction or uses herein illustrated and described but only as required by the spirit and scope of the appended claims.

Having thus described the invention, I claim:

1. An electrical circuit controlling apparatus of the type described comprising a two-way electrical switch; a timing mechanism; an electrical switch operatively associated with said timing mechanism to be periodically opened and closed thereby; and electrically conductive means adapted to connect a source of electrical power in series with an electrical appliance through one-half of said two-way switch, and to connect said appliance in series with. the source of electrical power through said second-mentioned switch and the other half of said two-way switch; whereby operation of said two-way switch to one position thereof provides a continuous energizing circuit for the appliance, and operation of said two-way switch to the other position thereof provides an energizing circuit for the appliance which is periodically opened and closed by said second-mentioned switch under control of said timing mechanism.

2. An electrical circuit controlling apparatus of the type defined in claim 1 and further comprising adjustable means for varying the periodical opening and closing of said second-mentioned switch by said timing mechanism.

3. An electrical circuit controlling apparatus of the type described comprising a two-way electrical switch; a clockwork mechanism; rotatable cam means driven by said clockwork mechanism; an electrical switch having an operating means adapted to be actuated by said cam means to periodically open and close a circuit; and electricall conductive means adapted to connect a source of electrical power in series with an electrical appliance through one-half of said twoway switch, and to connect said appliance in series with the source of electrical power through said second-mentioned switch and the other half of said two-way switch; whereby operation of said two-way switch to one position thereof provides a continuous energizing circuit for the appliance, and operation of said two-way switch to the other position thereof provides an energizing circuit for the appliance which is periodically opened and closed. by said second-mentioned switch under control of said timing mechanism.

4. An electrical circuit controlling apparatus of the type defined in claim 3 and in which said cam means is adjustable whereby the actuation of said second-mentioned switch may be varied.

5. An electrical circuit controlling apparatus of the type defined in claim 3 and in which said clockwork mechanism is electrically operated and is connected in series with the source of electrical power through said other half of said two-way switch whereby the clockwork mechanism is operated only when the appliance is to be periodically energized.

6. An electrical circuit controlling apparatus of the type defined in claim 3 and in which said cam means includes a plurality of axially spaced cams and the apparatus further comprises means to selectively position the said operating means of said second-mentioned switch for actuation by a selected one of said cams.

'7. An electric circuit controller of the type described comprising a unitary housing; a pair of electrically conductive members carried by said housing and adapted to be connected with a source of electrical power; an eletrical outlet in said housing; a two-way electrical switch in said housing; a timing mechenism in said housing; an electrical switch in said housing operatively associated with said timing mechanism to be periodically opened and closed thereby; a first electrical circuit connecting said members, said outlet and one-half of said two-way switch in series; and a second electrical circuit connecting said members, said outlet, said second-mentioned switch and the other half of said two-way switch in series; whereby connection of said members to a source of electrical power and operation of said two-way switch to one position thereof provides a continuous circuit for energizing an electrical appliance connected with said outlet, and operation of said two-way switch to the other position thereof provides an energizing circuit for the appliance which is periodically opened and closed by said second-mentioned switch under control of said timing mechanism.

8. An electric circuit controller of the type defined in claim '7 and further comprising adjustable means for varying the periodical opening and closing of said second-mentioned switch by said timing mechanism.

9. An electric circuit controller of the type de scribed comprising a unitary housing; a pair of electrically conductive members carried by said housing and adapted to be connected with a source of electrical power; an electrical outlet in said housing; a two-way electrical switch in said housing; a clockwork mechanism in said housing; rotatable cam means driven by said clockwork mechanism; an electrical switch in said housing having an operating means adapted to be actuated by said cam means to periodically open and close a circuit; a first electrical circuit connecting said members, said outlet and one-half of said two-way switch in series; and a second electrical circuit connecting said members, said outlet, said second-mentioned switch and the other half of said two-way switch in series; whereby connection of said members to a source of electrical power and operation of said two-way switch to one position thereof provides a continuous circuit for energizing an electrical appliance connected with said outlet, and operation of said two-way switch to the other position thereof provides an energizing circuit for the appliance which is periodically opened and closed by said secondmentioned switch under control of said clockwork mechanism.

10. An electric circuit controller of the type defined in claim 9 and in which said cam means is adjustable whereby the actuation of said second-mentioned switch may be varied.

11. An electrical circuit controller of the type defined claim 9 and in which said clockwork mechanism is electrically operated and is connected in series with the said members through said other half of said two-way switch whereby the clockwork mechanism is operated only when the appliance is to be periodically energized.

12. An electrical circuit controiler of the type defined in claim 9 in which said cam means include a plurality of axially spaced cams, the said controller further comprising means to selectively position the said operating means of said secondmentioned switch for actuation by a selected one of said cams.

13. An electric circuit controller of the type described comprising a unitary housing; an electrical plug carried by said housing and projecting therefrom for connection with an electrical power outlet; an electrical outlet mounted in said housing and accessible from the exterior thereof; a two-way electrical switch in said housing and having an operating member extending exteriorly of said housing; a timing mechanism in said housing; an electrical switch in said housing operatively associated with said timing mechanism to be periodically opened and closed thereby; a first electrical circuit connecting said plug, said outlet in said housing and one-half of said twoway switch in series; and a second electrical circuit connecting said plug, said outlet in the housing, said second-mentioned switch and the other half of said two-way switch in series; whereby insertion of said plug in an electrical power outlet and operation of said two-way switch to one position thereof provides a continuous circuit for energizing an electrical appliance connected with said outlet in the housing, and operation of said two-way switch to the other position thereof provides an energizing circuit for the appliance which is periodically opened and closed by said secondmentioned switch under control of said timing mechanism.

14. An electric circuit controller of the type described comprising a unitary housing; an electrical plug carried by said housing and projecting therefrom for connection with an electrical power outlet; an electrical outlet mounted in said housing and accessible from the exterior thereof; a two-way electrical switch in said housing and having an actuating member extending exteriorly of said housing; a clockwork mechanismin said housing; rotatable cam meansconnected for rotation by said clockwork mechanism; an electrical switch in said housing having an operating means adapted to be actuated by said cam means to periodically open and close a circuit; a first electrical circuit connecting said plug, said outlet in the housing, said second-mentioned switch and the other half of said two-way switch in series; whereby insertion of said plug in an electrical power outlet and operation of said two-way switch to one position thereof provides a continuous circuit for energizing an electrical appliance connected with said outlet in the housing, and operation of said two-way switch to the other position thereof provides an energizing circuit for the appliance which is periodically opened and closed by said second-mentioned switch under control of said clockwork mechanism.

15. An electric circuit controller of the type defined in claim 14 and in which said cam means is adjustable whereby the actuation of said secend-mentioned switch may be varied.

16. An electric circuit controller of the type defined in claim 14 and in which said clockwork mechanism is electrically operated and is connected in series with the said plug through said other half of said two-way switch whereby the clockwork mechanism is operated only when the appliance is to be periodically energized.

17. An eiectric circuit controller of the type defined in claim 14 and in which said cam means includes a plurality of axially spaced cams, the said controller further comprising means to selectively position the said operating means of said second-mentioned switch for actuation by a selected one of said cams.

18. An electrical circuit controller comprising a manually operable switching means including a movable conductive means and spaced stationary electrical contacts adapted to be selectively engaged by said movable means to provide two independent paths for electrical power through the said switching means, a first electrical circuit including electrical conductors adapted to connect an electrical appliance in series with a source of electrical power through one of said independent paths therefor of the switching means when the movable means is actuated to one position, and a second electrical circuit including a periodically operated switch and electrical conductors adapted to connect the said electrical appliance in series with said source of electrical power through the other of said independent paths therefor of the switching means when the movable means is actuated to another position, whereby the said appliance may be selectively continuouslyv energized through said first circuit or periodically energized through said second circuit.

19. An electrical circuit controller comprising a manually operable switching means including a movable conductive means and spaced stationary lectrical contacts adapted to be selectively engaged by said movable means to provide two independent paths for electrical power through said switching means, a first electrical circuit including electrical conductors adapted to connect an electrical appliance in series with a source f electrical power through one of said independent paths therefor of the switching means when the movable means is actuated to one position, an electrically operated timing device, an electrical switch periodically operated by said timing 11 device, a second electrical circuit including electrical conductors adapted to connect the said electrical appliance in series with said source of electrical power through the periodically operated switch and the other of said independent paths of the switching means, and other electrical conductors adapted to connect said electrical timing device to said source of electrical power through the said other path of said switching means and in parallel with said periodically operated switch and appliance, whereby the said appliance may be selectively continuously energized through said first circuit or periodically energized through said second circuit and the said timing device is operated only when the appliance is connected for periodic energization.

GEORGE B. LUTZ.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 10 Number Name Date 1,763,138 E'delmann June 10, 1930 2,206,114 O bodyinski July 2, 1940 2,357,061 Stattner Aug. 29, 1944 

